Glucose Transporter Deficiency Syndrome (GLUT-1): Case Report and Novel Pathogenic Variant of the SLC2A1 Gene

Glucose transporter 1 deficiency syndrome (GLUT-1 DS) is caused by mutations in the SLC2A1 gene in most patients, resulting in impaired glucose transport to the brain. A variety of phenotypes may present, including epilepsy, intellectual disability, and movement disorders. Objective: To report a case of GLUT-1 DS associated with a new variant of the SLC2A1 gene. Clinical Case: A six-year-old female patient diagnosed with refractory epilepsy at the age of two. Pharmacological management was initiated when she was four years old. Microcephaly and delayed neurodevelopment were observed. She was admitted due to an exacerbation of seizures. A genetic panel revealed a variant in the SLC2A1 gene (A>T), which replaces the amino acid phenylalanine at codon 434 with isoleucine (p.Phe434Ile). This variant has not been previously described in the medical literature but is likely pathogenic. Biochemical analysis of cerebrospinal fluid glucose showed hypoglycorrhachia, confirming the diagnosis. A ketogenic diet was initiated, leading to a marked reduction in seizures. Conclusions: GLUT-1 DS is a rare neurometabolic disease, in which timely diagnosis is essential to initiate the primary treatment with a ketogenic diet. This approach has been demonstrated to be the treatment of choice for seizure control and may also have a positive impact on cognitive and motor function. The presented case features a variant in the SLC2A1 gene that can be considered pathogenic.